Periodontitis is a chronic inflammatory disease that affects the interface of teeth and surrounding tissues. Gingival crevicular fluid (GCF) is an exudate of the periodontal tissues and can be collected from the gap between the tooth and gum (gingival sulcus or periodontal pocket) with paper strips. Testing of GCF is a low‐cost and minimally invasive procedure. In a variety of diseases, microRNAs (miRNAs) in body fluids are implicated in pathogenesis, and are suggested as potential diagnostic biomarkers. Here, we profiled miRNAs in GCF (two chronic periodontitis, one aggressive periodontitis, and five healthy subjects) using miRCURY LNA™ Universal RT microRNA PCR System, which yielded quantitative measures of more than 600 miRNAs. Through this analysis, we found that miRNA profiles in GCF of periodontitis patients are distinct from those of healthy controls. We further selected 40 miRNAs and confirmed their differential expression patterns in different subjects (five chronic periodontitis, one aggressive periodontitis, and six healthy subjects) using a custom miRNA PCR panel. This is the first demonstration of miRNA profiling in GCF and its alteration in periodontitis. Our findings suggest that a subset of miRNAs in GCF holds potential as a biomarker for periodontitis.

The aim of this study is to analyze the relationship between Hepatocyte Growth Factor (HGF) levels in oral rinses using water and clinical parameters of periodontitis; and furthermore, to evaluate the potential of a prototype HGF immunochromatographic paper test strip (HGF-TS) for screening of periodontitis, in comparison with a commercially-available occult blood (hemoglobin) test strip (Hb-TS). Clinical periodontal parameters were recorded, and oral rinses were collected, from 125 subjects. Then, the presence of HGF, and hemoglobin (Hb), in each sample was detected using a prototype HGF-TS and an Hb-TS. In addition, the concentrations of HGF and Hb were also determined in each sample is necessary HGF concentrations in oral rinses showed significant correlations with clinical parameters of periodontitis. The positive rate and read value on HGF-TS showed significantly high values in cases of severe periodontitis compared to healthy subjects. Hb-TS showed generally higher positive rates than HGF-TS; however, it showed false positive results in healthy subjects. The concentration of HGF in oral rinses showed close association with the severity of periodontitis, suggesting that the prototype HGF-TS has potential for use in the diagnosis of periodontitis, although further refinement of the test strip is required to increase the sensitivity. Keywords; hepatocyte growth factor, immunochromatgraphic paper, mass-screening test, occult blood test, periodontitis Materials and Methods Subjects and clinical evaluation of periodontal status A total of 125 subjects (60 male and 65 female) participated in this study. The subjects with periodontal disease were patients of the Department of Periodontics, Dental Hospital of Tokyo Medical and Dental University (TMDU). The healthy subjects were volunteers consisting of dentists in the Department of Periodontology, TMDU, as well as dentists and hygienists from private dental offices. Written informed consent for participation was obtained from all individuals. This study was approved by the Ethics Committee of the Faculty of Dentistry, TMDU (#1209), and the study was conducted in accordance with the Helsinki Declaration of 1975, as revised in 2013, and the ethical guidelines for epidemiology research of 2002, as revised in 2008 (Ministry of Health, Labor and Welfare, Japan). Subjects were selected according to the following criteria: absence of systemic diseases, no systemic antibiotics taken in preceding 3 months, and no pregnancy or lactation. Participants underwent a full-mouth periodontal examination including probing pocket depth (PD) and bleeding on probing (BOP) at all six sites of each tooth, as well as tooth mobility. Examinations were conducted by each patient's dentist. Radiographic examination (bisecting angle technique) was performed for some of the periodontitis patients and healthy subjects, and bone crest level (BCL) was determined. BCL was defined as the vertical distance (mm) from cementoenamel junction (CEJ) to the most crestal point of marginal bone [19-21], and w...